Generally, rotors of an electric generator, a steam turbine, a gas turbine, or a compressor, for example, are coupled coaxially by a rotor coupling (see Patent Document 1).
In the steam or gas turbine, gas seals (called mechanical seals) 101 may be installed at portions of a rotor 100 which penetrate a turbine casing, as shown in FIG. 15. These are 360° circular (endless) components fitted from the shaft ends of the rotor 100. The gas seal 101 needs to be periodically detached and attached for maintenance and checkup.
To enable the gas seal 101 to be detached and attached, therefore, a rotor coupling 102A, which is installed at the shaft end of the rotor 100, is also designed to be capable of easy removal and reassembly. In the illustrated example, for instance, a coupling sleeve 102a of the rotor coupling 102A is increased in diameter by application of a hydraulic pressure (see hydraulic paths 103 in the drawing), and then the hydraulic pressure is released, whereby the coupling sleeve 102a is interference-fitted (hydraulically fitted) to the shaft end of the rotor 100. From this state, on the other hand, a hydraulic pressure is applied again to increase the diameter of the coupling sleeve 102a, whereby the rotor coupling 102A can be removed from the shaft end of the rotor 100.
As shown in FIG. 16, moreover, there is a case in which an involute spline tooth portion 104a cut in the outer periphery of the shaft end of a rotor 100, and an involute spline groove portion 104b cut in the inner periphery of a coupling sleeve 102b of a rotor coupling 102B are brought into splined engagement with each other, and prevented by a press nut 105 from disengagement.
Patent Document 1: JP-A-2003-65006